In mixing of immiscible liquids, two rivaling processes of break-up and coalescence of drops occur simultaneously. The intensity of both processes and, therefore, the results of emulsification are determined by local mixing intensity (shear rate, specific power, etc.) which, in turn, depends on characteristics of tank and impeller, and on the physical properties of the initial fluids.

VisiMix simulates the formation of the emulsion, determines if complete emulsification is achieved, calculates mean drop size, specific mass transfer area, mixing time, and other process parameters important for emulsification, liquid extraction, multiphase chemical reactions etc.

Problem description:

A liquid – liquid emulsification process is carried out in a cylindrical, baffled tank with an elliptical bottom. The parameters of the mixing system are as follows:

Initial data:

• Tank Elliptical bottom:
• Inside diameter = 500 mm
• Total volume = 100 L
• Volume of media = 90 L

Baffle (flat type, attached at a distance from the wall):

• Number = 4
• Width = 50 mm;
• Length = 451 mm;
• Distance from bottom = 100 mm.
• Distance from wall = 15 mm
• Angle to radius = 0 deg.

Impeller (DISK TURBINE):

• Tip diameter = 200 mm
• Diameter of disk = 150 mm
• Number of blades = 6
• Pitch angle = 90 deg.
• Width of blade = 40 mm
• Length of blade = 50 mm
• Distance from bottom = 100 mm.
• Rotational speed = 250 rpm
• Power of drive = 500 W

Media properties:

The media is a pure oil – water system without significant admixtures with the interfacial surface tension = 0.03 N/m;

Continuous phase (water) properties:

• Density = 1000 kg/cub. m;
• Dynamic viscosity = 0.001 Pa*s;

Disperse phase (pure oil) properties:

• Volume fraction = 0.3;
• Density = 940 kg/cub. m;
• Dynamic viscosity = 0.03 Pa*s;
• Index of repulsing pressure = 0